Publication on the effectiveness of one-sided window impulse ventilation in classrooms
Using complex numerical flow simulations, the EBC has published a study on the evaluation of one-sided window ventilation according to the shock ventilation principle.
In the simulation, a classroom is modelled over one school hour with 28 pupils and one teacher. The classroom has a typical window-front through which ventilation is carried out according to the 20/5/20 rule ("UBA recommendation"). Window ventilation is investigated using three outdoor air temperatures (5 °C, 15 °C and 20 °C) as examples. The effectiveness of the ventilation is evaluated based on the ventilation efficiency, which is derived from the course of the CO2 concentration during the ventilation phase, and the achievable air change. In addition, the influences on thermal comfort during window ventilation are investigated and evaluated.
Based on the results, it can be shown that the outside air temperature has a high influence on both the ventilation effectiveness and the thermal comfort. At low outdoor air temperatures, a high air exchange rate is achieved and thus also a significant reduction in CO2 concentration. In this case, however, the thermal comfort limit of 20 °C is not reached for a long time. The ventilation efficiency increases with higher outdoor air temperatures, as the fresh air brought in flows into the room with less impulse and thus affects the stratification less.
Link to publication (published in German)